Where are the twinkies?

Question

You have been stranded on an island in the middle of the ocean for the past 26 days, and your food supply is starting to run low. Unfortunately the only person on the island that has any knowledge about gathering food from the wilderness has told you that pretty much every fruit-bearing plant on the island produces some form of toxin that prevents you from being able to eat it for a long period of time without needing medical attention.

As a group, you decide to all go looking for anything that might be edible. You (being quite athletic and able to make your way back to the camp, or pitch your own if night should fall) go off by yourself down the beach. After a couple hours of walking and not finding anything, you decide to sit down and take a break. No need to exhaust yourself, especially if there isn't a good chance you'll be able to find any food. Sitting there taking in your surroundings, a glimmer catches your eye 8 yards and 2 feet down from where you are. You walk over to see what it might be and find a corked bottle. You can faintly see something that looks like crumpled paper inside (it's hard to tell through the dirty glass). You quickly pop the cork off to find two pieces of paper:

Lifetime Twinkie Supply Giveaway FINAL CLUE - You're almost there!!

You remember back a couple years ago when there was a big treasure hunt for a lifetime supply of twinkies that just kind of faded and everyone figured was just a scam to get people to buy twinkies for the clues inside. You remind yourself of the second note, before getting caught up in why there was never a lawsuit surrounding that "giveaway". It says:

This is the final clue to the Twinkie Giveaway. If you've gotten this far, then all you need to do is solve this riddle to figure out where on the horseshoe island the twinkies are hidden.

You are shocked for a moment. You have walked around your island enough times to realize that the big bay going into the middle would make it look exactly like a horseshoe from overhead. You try to contain your excitement of the possible lifetime supply of food as you read on:

We have created a cipher for you to solve. First, you can know that:
THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG
encodes to:
XZC AMKKQ DROQZ BKB XECXM ABSH RLW JKRA LUI
This probably wouldn't be much help without another phrase that you need to decode to actually find the final location, so here you go:
XZCDOKVQKESUDAERGSTMNTKPYEXJCO

You will probably end up getting Lost, but the Number of hints we can give is limited, so you only get one more:
SLDUXOESQPSOCFEVALZMSTIIFKXCDFOXSDEQPOLVDGALSKCDZG
PADEFNANOJDNGFERDUIVCZENMFASDJNVAOUWENHFATJVNAOIUV
AOIWWEHIUNASDNCEFNOWEIKFNACVNSIJCVNAIUEFWEEIUFOASU
QOWYUIQIRUIDOFSANOIUSDPFHUAFWEBGFDVZBVOIDAGUUNTHIB
AJWNIEFGAIUVFNRAIUNAIUMEWNAWUINGIJNFAWIDNWAIFDJNGA
TOIIPTETORJQOIHXJQNWMGLBOUAENQSVONVCAJSDNEWJGNWBUJ
QPETOERTUIVNMXERNDMLKMSMVMAJSHFIUXLASHUVH.EOSLDKFJ

Using your cunning sense of reasoning, you determine that the twinkies are probably going to be in some sort of landmark on the island, seeing as you have a very short clue, so there couldn't be any step by step instructions. The only problem is that there are a bunch of landmarks on the island. There's both parts of the "horseshoe", a big black rock, a small river that passes through part of the island, a huge tree at one end of the horseshoe, a patch of beach that has much darker sand, and many more. You figure that by the time you were able to send people to each of these places to search for twinkies, everyone would have already starved. So the only way to get them would be solving the riddle.

So, where are the twinkies?

Thanks to Quarks, you've discovered the location of the twinkies, but when you get there, you find a computer that requires you to type in a password to open the safe full of twinkies (unfortunately the ethernet cable has been chewed away by mice so you can't check your facebook or ask for help). Perhaps it has something to do with that last hint that you got. Figure out what the password is before everybody starves!!

Answer 1

To accompany Quark's correct answer, the hint decodes to:

"Use Vigenere twice key is a pangram with X letters." and X = 26

The clues are:

the capital letters for Lost and Number which suggests using the numbers from this television series. These numbers are 4, 8, 15, 16, 23 and 42. Using letters from these columns of the cipher text (shown below in yellow) provides the decoded sentence.

Then, the number of letters in the key (X) is 26 based on the clues "26 days" and "26 feet". In addition, the Vigenere key in Quark's answer does have 26 letters.

As the encryption needs to be applied twice, the key works out to be:

"Cwm fjord bank glyphs vext quiz" which is a notable pangram.

According to anagrammy.com, this pangram means "carved figures in a valley on a bank of a fjord irritated an eccentric person". Cwm is Welsh for a circular valley; a glyph is a carved figure; vext is the poetic spelling of vexed; and a quiz is an 18th-century term for an eccentric.

Answer 2

I don't think I solved this the way I was supposed to because I didn't use the last hint.

The answer is "THE TWINKIES ARE INSIDE THE BIG TREE"

Method:

Based on the "THE"s corresponding to XZC both RLW I immediately thought it could be similar to a vigenere cipher. So, using a solver, I converted "THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG" to "XZC AMKKQ DROQZ BKB XECXM ABSH RLW JKRA LUI" and got a key of "esykscigcaaumwweokqiumgoqy".

Using this key for vigenere decryption, the solution string can be decoded.